On Sun, 2021-06-13 at 12:21 +0200, Hans de Goede wrote:
On x86/ACPI platforms touchscreens mostly just work without needing
any
device/model specific configuration. But in some cases (mostly with
Silead
and Goodix touchscreens) it is still necessary to manually specify
various
touchscreen-properties on a per model basis.
This is handled by drivers/platform/x86/touchscreen_dmi.c which
contains
a large list of per-model touchscreen properties which it attaches to
the
(i2c)device before the touchscreen driver's probe() method gets
called.
This means that ATM changing these settings requires recompiling the
kernel. This makes figuring out what settings/properties a specific
touchscreen needs very hard for normal users to do.
Add a new, optional, settings_override string argument to
touchscreen_parse_properties(), which takes a list of ; separated
property-name=value pairs, e.g. :
"touchscreen-size-x=1665;touchscreen-size-y=1140;touchscreen-swapped-
x-y".
This new argument can be used by drivers to implement a module option
which
allows users to easily specify alternative settings for testing.
The 2 new touchscreen_property_read_u32() and
touchscreen_property_read_bool() helpers are also exported so that
drivers can use these to add settings-override support to the code
for driver-specific properties.
Signed-off-by: Hans de Goede <redacted>
---
Note instead of patching all touchscreen drivers we could also rename
touchscreen_parse_properties() to
touchscreen_parse_properties_with_override()
and add a static inline wrapper which passes NULL. Just patching the
drivers
feels a bit cleaner to me though.
It would be easier to do that in a separate commit, or separate
commits, keeping just the new parsing code separate, even if you remove
the _with_override() variant the next commit.
I haven't reviewed the argument parsing code, but eep. If this were
user-space code, we'd have exported it and tried to feed it all kind of
garbage to see whether it parsed things properly, even if it's only run
on the author's machine. Can't say that I like it.
Cheers